This chapter covers Microsoft To Do and its role in personal task management within Microsoft 365. For the MS-900 exam, understanding how To Do integrates with Outlook Tasks, Planner, and the Microsoft 365 ecosystem is essential. Questions on this topic typically represent 5-8% of the exam, focusing on features, integration points, and the distinction between personal and collaborative task management. You will learn the exact mechanisms, defaults, and exam traps.
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Imagine you are a busy executive with multiple projects, each with its own set of tasks. Your personal assistant, Alex, manages all your to-dos. Alex has a master notebook where every task is recorded: "Prepare quarterly report," "Book flight for client meeting," "Review contract," etc. Each task has a due date, priority, and notes. Alex also maintains separate project folders: one for Q4 planning, one for client travel, one for legal reviews. These folders are like Microsoft To Do's lists. When you ask Alex, "What do I need to do today?" Alex refers to a special section called "My Day" — a curated list of tasks you plan to tackle today, which can be pulled from any project folder. If you delegate a task to a colleague, Alex can assign it to that person, and the task appears in their own master notebook (like Planner integration). The magic is that all these views — the master notebook, project folders, today's list, and delegated tasks — are synchronized in real time. If you mark a task complete in your "My Day" view, it is instantly marked complete in the project folder and in your colleague's view. Alex never duplicates work; every task exists once in the master notebook but can appear in multiple filtered views. This is exactly how Microsoft To Do works: every task lives in Exchange Online as a task item, and lists, My Day, and flags are just different filters on the same underlying data.
What is Microsoft To Do?
Microsoft To Do is a cloud-based personal task management application that synchronizes across all devices via Exchange Online. It replaced the classic Tasks feature in Outlook and Wunderlist, bringing a clean, cross-platform interface. The service is included in all Microsoft 365 subscriptions, including Business Basic, Business Standard, Enterprise E3/E5, and even free Outlook.com accounts.
How It Works Internally
Every task created in Microsoft To Do is stored as a Task item in the user's Exchange Online mailbox, specifically in the Tasks folder (IPF.Task). This is the same underlying data structure used by Outlook Tasks. When you create a task in To Do, it writes to Exchange; when you update a task in Outlook, it reflects in To Do. The synchronization is near-instantaneous via Exchange Web Services (EWS) or Microsoft Graph API, depending on the client.
To Do adds a layer of organization on top of raw tasks: - Lists: A list is a folder-like grouping of tasks. Each list corresponds to a task folder in Exchange. The default list is "Tasks" (the same as Outlook's Tasks folder). Users can create additional lists like "Work," "Personal," etc. Each list is a separate subfolder under the Tasks folder. - My Day: This is a smart, daily view that shows tasks you plan to complete today. My Day is not a separate storage location; it is a filtered view of tasks from any list that you have added to My Day. Adding a task to My Day sets a property on the task item (flag due date) to today's date. You can add tasks from any list to My Day, and they remain in their original list. - Suggested Tasks: To Do uses AI to suggest tasks for My Day based on your past behavior, such as recurring tasks or tasks you typically do on a given day. These suggestions are powered by Microsoft Graph machine learning models running on Exchange Online data. - Steps: A task can have multiple steps, which are sub-items stored as child task items or as extended properties on the parent task. Steps are not separate tasks; they are part of the same task object. - Reminders and Due Dates: Each task can have a due date and a reminder. Reminders trigger via the To Do app or Outlook notifications, and they are stored as alarm properties on the task item. - Files and Notes: Attachments (files) are stored in Exchange as item attachments (up to 32 MB per attachment). Notes are plain text stored in the task body.
Key Components and Defaults
Task Limit: A user can have up to 300,000 tasks in their mailbox. However, performance degradation may occur beyond 100,000 tasks. To Do itself shows up to 10,000 tasks per list for performance reasons.
List Limit: A maximum of 500 lists per user (including the default Tasks list).
My Day Limit: No hard limit, but the UI is optimized for 20-30 tasks per day.
Steps per Task: Up to 100 steps per task.
Reminder Default: None when creating a task; users must set explicitly.
Due Date Default: None; tasks are created with no due date unless specified.
Sync Interval: Exchange ActiveSync (EAS) syncs tasks every 15 minutes on mobile; desktop apps sync near-real-time via push notifications.
Integration with Outlook
Microsoft To Do and Outlook Tasks share the same data store. Any task created in Outlook (in the Tasks module) appears in To Do, and vice versa. However, there are some differences: - Categories: Both use Outlook categories. To Do's list colors correspond to category colors. When you create a list in To Do, it creates a corresponding category in Outlook. - Flagged Emails: In Outlook, you can flag an email, which creates a task in the Tasks folder. This flagged email appears as a task in To Do's "Flagged Email" list (a system list). In To Do, you cannot create a task from an email directly; you must use Outlook for that. - Task Status: Outlook tasks have status fields (Not Started, In Progress, Completed, Waiting on someone, Deferred). To Do does not display these statuses; it uses a simpler completion checkbox. However, the status is preserved in Exchange and can be seen in Outlook.
Integration with Planner
Microsoft Planner is a collaborative task management tool for teams, with tasks stored in a Planner plan (which is backed by a SharePoint list and a Microsoft 365 Group). To Do can show tasks from Planner if the user is a member of the plan. This integration works via the "Assigned to me" feature: when a Planner task is assigned to you, it appears in To Do's "Assigned to me" list. This is a read-only view in To Do; you cannot edit Planner task details from To Do except marking it complete (which updates the Planner task).
Integration with Microsoft 365 Copilot (AI)
Copilot in To Do can help you create tasks, summarize tasks, and suggest next actions. It uses the same Graph API and machine learning models. Copilot can also analyze your tasks and suggest grouping or prioritization.
How to Configure and Verify
To Do is enabled by default for all Microsoft 365 users. Administrators can disable To Do via the Microsoft 365 admin center (Settings > Org Settings > Microsoft To Do). To verify the integration is working: 1. Open Outlook Web App (OWA) and create a task in the Tasks folder. 2. Open Microsoft To Do app (desktop or mobile) and confirm the task appears. 3. Create a list in To Do and verify it appears as a category in Outlook. 4. In Planner, assign a task to yourself and check the "Assigned to me" list in To Do.
Interaction with Related Technologies
Exchange Online: The backbone; all tasks stored here.
Microsoft Graph: Used by To Do to access task data, especially for AI features and third-party integration.
SharePoint Online: Planner tasks are stored in SharePoint lists; To Do reads them via Graph.
Teams: To Do can be pinned as a tab in Teams, showing the user's tasks.
Power Automate: Can create and update tasks in To Do, enabling automation scenarios.
Exam-Relevant Details
Data Storage: Tasks are stored in Exchange Online, not in a separate database.
Sync: Real-time sync via Exchange Web Services.
My Day: Not a separate list; it's a filter based on due date or manual addition.
Flagged Emails: Only appear in To Do if flagged in Outlook; they appear in a special system list.
Planner Tasks: Read-only in To Do except for completion status.
Create a Task in To Do
A user opens the To Do app (desktop, mobile, or web) and clicks 'Add a task'. They type a title and optionally add due date, reminder, notes, and steps. When they press Enter, the client sends a request to Exchange Online via the Graph API or EWS to create a new Task item in the Tasks folder (IPF.Task). The task is assigned a unique ID (the PidTagSearchKey and PidTagEntryId). The server stores the task and immediately returns a success response. The client then updates its local cache. If the user added the task to a specific list (e.g., 'Work'), the client sets the task's folder to the corresponding subfolder under Tasks.
Add Task to My Day
The user clicks on a task and selects 'Add to My Day'. The client sends a PATCH request to Exchange to update the task's flag due date to today's date (or to set a custom property indicating it is in My Day). The server updates the task item. The My Day view in the client queries all tasks that have a flag due date equal to today (or the custom property). This is a filter, not a move. The task remains in its original list. If the user later removes it from My Day, the flag due date is cleared (set to None).
Sync Across Devices
When a task is created or modified on one device, the change is sent to Exchange Online. The server updates the task item and sends a push notification (via Exchange ActiveSync or WebSocket) to all other devices subscribed to the Tasks folder. The receiving client receives the change and updates its local cache. For mobile devices using EAS, the sync occurs every 15 minutes or on demand when the app is opened. Desktop and web clients use push notifications for near-real-time sync (typically under 5 seconds). If a conflict occurs (e.g., two devices modify the same task simultaneously), Exchange uses 'last writer wins' — the most recent modification is kept.
View Planner Tasks in To Do
When a user opens the 'Assigned to me' list in To Do, the client makes a Graph API call to retrieve all Planner tasks assigned to the user across all plans they are a member of. The Graph API returns a list of tasks with their properties (title, due date, priority, etc.). To Do displays these tasks as read-only items. If the user marks a Planner task as complete in To Do, the client sends a PATCH request to the Graph API to update the task's percentComplete to 100. The Planner backend updates the task and triggers notifications to other plan members. Note that the user cannot edit the task title, due date, or assignment from To Do; they must use Planner.
Admin Disable To Do
A Microsoft 365 global admin navigates to the Microsoft 365 admin center > Settings > Org Settings > Microsoft To Do. They toggle the setting 'Let people in your organization use Microsoft To Do' to off. This sets an organization-wide policy that blocks access to the To Do service. The change is propagated via Azure AD Conditional Access or through the service configuration. Users will see an error message when trying to open To Do: 'Your organization has disabled this service.' This does not delete existing tasks; they remain in Exchange. If the admin re-enables To Do, users regain access. Alternatively, an admin can block To Do using a SharePoint Online or Exchange Online policy, but the admin center method is the simplest.
Enterprise Scenario 1: Sales Team Task Management
A sales team of 50 uses Microsoft To Do for personal daily task tracking. Each salesperson has lists: 'Prospecting', 'Follow-ups', 'Contract Reviews'. They use My Day to focus on daily priorities. The sales manager uses Planner for team-wide task assignments. Integration allows each rep to see their assigned tasks in To Do's 'Assigned to me' list. The problem solved: reducing email overload by centralizing tasks. Config: To Do is enabled by default; no special admin setup. Performance: with 50 users each having ~500 tasks, sync is seamless. Common issue: reps forget to check Planner for updates; To Do's read-only view lacks details like comments and checklists, causing confusion. Mitigation: train reps to use Planner for collaborative tasks and To Do for personal ones.
Enterprise Scenario 2: IT Help Desk Ticketing
An IT department uses a Power Automate flow to create a To Do task when a help desk ticket is assigned to a technician. The flow triggers on a SharePoint list update, creates a task in the technician's 'IT Tickets' list with due date and priority. Technicians use My Day to prioritize tickets. This replaces a costly third-party tool. Config: Power Automate license required (included with Microsoft 365 E3/E5). Scale: 20 technicians, 100 tickets/day. Problem: if a technician accidentally deletes a task, the ticket is lost. Best practice: use a separate system for ticket tracking and only create tasks as reminders.
Enterprise Scenario 3: Executive Personal Assistant Workflow
An executive assistant manages the CEO's tasks using Microsoft To Do. They create lists for 'Board meetings', 'Travel', 'Personal errands'. The CEO uses My Day to see what's planned. The assistant can assign tasks to the CEO (via Outlook Tasks) but cannot directly create tasks in the CEO's To Do unless they have delegate access. Config: delegate access set up via Exchange (full mailbox permissions). Scale: single user with 2000 tasks. Performance: no issues. Common misconfiguration: the assistant creates tasks in their own To Do and then tries to share the list (not supported). Correct approach: use Outlook Tasks with delegation.
What MS-900 Tests on This Topic
Objective 2.4: Describe productivity solutions in Microsoft 365. Specifically, you need to know:
The purpose of Microsoft To Do (personal task management).
How it integrates with Outlook Tasks (same data store, Exchange Online).
How it integrates with Planner (read-only view of assigned tasks).
The concept of My Day (daily filter, not separate storage).
The difference between personal (To Do) and collaborative (Planner) task management.
Common Wrong Answers and Why
'To Do tasks are stored in SharePoint.' Wrong. They are stored in Exchange Online. Candidates confuse Planner (SharePoint-backed) with To Do.
'My Day is a separate list.' Wrong. My Day is a filtered view. The exam may present: 'You can organize tasks into My Day lists.' This is false; My Day is not a list.
'You can assign tasks to others in To Do.' Wrong. To Do is personal; you cannot assign tasks to others. Only Planner allows assignment.
'To Do is only available in paid subscriptions.' Wrong. It is also available in free Outlook.com.
Numbers and Terms That Appear on the Exam
Exchange Online as the storage backend.
'My Day' as a daily planning view.
'Flagged Email' list for emails flagged in Outlook.
'Assigned to me' list for Planner tasks.
Lists (up to 500) for grouping tasks.
Steps (up to 100) for sub-tasks.
Edge Cases and Exceptions
If a user deletes a list in To Do, all tasks in that list are moved to the default 'Tasks' list (not deleted). The exam might test this.
To Do does not support recurring tasks natively; you must create each occurrence or use the 'Repeat' feature which creates a new task on the due date.
Sharing a list is not possible; To Do is personal. However, you can share a task via Outlook (forward as email).
How to Eliminate Wrong Answers
If a question asks about task storage, eliminate any answer mentioning SharePoint or OneDrive — it's Exchange. If it mentions 'team tasks' or 'assignment', it's about Planner, not To Do. If it mentions 'daily view' or 'focus', it's My Day.
Microsoft To Do stores tasks in Exchange Online, not SharePoint.
My Day is a filtered view, not a separate storage location.
To Do is for personal tasks; Planner is for collaborative tasks.
Flagged emails from Outlook appear in To Do's 'Flagged Email' list.
Planner tasks appear read-only in To Do's 'Assigned to me' list.
A user can have up to 500 lists and 300,000 tasks.
Deleting a list moves tasks to the default Tasks list.
To Do is included in all Microsoft 365 subscriptions and free Outlook.com.
These come up on the exam all the time. Here's how to tell them apart.
Microsoft To Do
Personal task management
Tasks stored in Exchange Online
No assignment to others
My Day view for daily focus
Lists for personal organization
Microsoft Planner
Team task management
Tasks stored in SharePoint lists
Assign tasks to team members
Board and chart views for team
Buckets and labels for organization
Mistake
Microsoft To Do stores tasks in SharePoint Online.
Correct
Tasks are stored in Exchange Online, in the user's mailbox Tasks folder. Planner tasks are stored in SharePoint lists.
Mistake
My Day is a separate list you can create multiple of.
Correct
My Day is a single, daily filtered view of tasks from any list. You cannot have multiple My Day lists.
Mistake
You can assign tasks to other people in To Do.
Correct
To Do is for personal task management. Task assignment requires Planner (collaborative) or Outlook Tasks with delegation.
Mistake
Deleting a list deletes all tasks in it.
Correct
When you delete a list, tasks are moved to the default 'Tasks' list. They are not deleted unless you manually delete them.
Mistake
Microsoft To Do is only available with Microsoft 365 Enterprise subscriptions.
Correct
To Do is available with all Microsoft 365 subscriptions, including Business Basic, Business Standard, Enterprise, and even free Outlook.com accounts.
Reveal each answer, then mark whether you got it right. Score 60%+ to unlock the next chapter.
Microsoft To Do tasks are stored as Task items in the user's Exchange Online mailbox, specifically in the Tasks folder (IPF.Task). This is the same storage used by Outlook Tasks, ensuring seamless synchronization. The tasks are not stored in SharePoint or OneDrive.
A list is a folder-like grouping of tasks (e.g., Work, Personal) where tasks are permanently stored. My Day is a daily filtered view that shows tasks you plan to complete today, pulled from any list. Adding a task to My Day does not move it; it just sets a flag due date. You can have many lists but only one My Day per day.
No, Microsoft To Do is for personal task management only. You cannot assign tasks to other users within To Do. For team task assignment, use Microsoft Planner, which allows assigning tasks to group members and tracking progress.
When you flag an email in Outlook, it creates a task in your Tasks folder with a link to the email. In Microsoft To Do, these flagged emails appear in a special system list called 'Flagged Email'. You can view and complete them there, but you cannot create flagged emails from within To Do.
When you delete a list, all tasks in that list are moved to the default 'Tasks' list. They are not permanently deleted. You can still access them from the Tasks list. Only if you manually delete individual tasks from the Tasks list are they permanently removed.
Yes, Microsoft To Do is available for free with a Microsoft account (Outlook.com). It is also included in all Microsoft 365 subscriptions, including Business and Enterprise plans. The free version has the same core features as the paid version.
Yes, if you are assigned a task in a Planner plan, it appears in To Do's 'Assigned to me' list. However, this is a read-only view; you can mark the task complete, but you cannot edit the title, due date, or other details from To Do. Full editing requires Planner.
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